a. Field of the Invention
The instant invention relates to methods and apparatus for scanning a site of interest and providing information about structures within and around the site. In particular, the instant invention relates to rotationally-scanning transducers (e.g., ultrasound transducers, optical transducers such as infrared radiation and optical coherence tomography (OCT) transducers, and the like) that provide visualization of and/or information about adjacent structures.
b. Background Art
Ultrasound transducers are utilized in a variety of medical applications. In many applications, the transducer is mounted in a catheter than can be navigated through a patient's vasculature to a site of interest.
In many such catheters, the transducer is rotated around a longitudinal axis of the catheter in order to perform a B-scan in a plane perpendicular to the axis of the catheter. Such a catheter is referred to herein as a “rotationally-scanning ultrasound catheter.” The transducer may be rotated via a motor or a manual actuator (e.g., a finger slider), either of which necessitates a relatively complex, relatively large diameter, and expensive catheter structure. For example, a motorized rotating transducer typically requires a rotating drivewire, a rotating energized (“hot”) lead, and a rotating ground lead, as well as electrical slip rings in the catheter handle.